Caller ID is a service that determines and communicates the number/name of the calling party of an incoming call to the called device (i.e., a phone). Many modern telephone and telephony systems routinely offer this service, which is also known as Automatic Number Identification (ANI). Caller ID is also offered on communication systems that provide telephony services via packet-based networks, i.e., those that operate in accordance with the Internet Protocol (IP).
Ring tones—especially ones that include clips of familiar musical songs—are quickly becoming a popular way to identify a caller. A ring tone is any audio, video, or audio/video file or clip played at a mobile client device (i.e., mobile phone) to indicate an incoming call. For instance, a ring tone might consist of several bars of a familiar musical tune, and may also include a person's voice, or other distinctive sounds. The proliferation of mobile (cellular) telephones in recent years has given rise to a wide variety of ring tones. A user of a typical mobile phone may statically configure or set a predetermined ring tone for each individual in his personal address book. When an incoming call from an individual is received by the mobile phone, the caller ID is looked up in the phone's internal address book, and the associated ring tone is played to announce the call. One problem with this approach is that the association of the caller with the ring tone happens at the phone itself and is extremely static; that is, the user needs to manually configure the custom ring tone in his local address book on a person-by-person basis. This can be an arduous task when the number of entries in a person's address book is very large.